Compressor control mechanism



Nov. 23, 1948. w. H. WINEMAN 2,454,363

COMPRESSOR CONTROL MECHANISM Filed Dec. 9, 1944 4 Shee'ts-Sheet 1 1291.

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' COMPRESSOR CONTROL MECHANISM Filed Dec. 9,4944 4 Sheets-Sheet 2 nya w yy 96 76 ZJade 12217322622200.

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COMPRESSOR. CONTROL MECHANISM Filed Dec." 9, 1944 4 Sheets-Sheet 5 2 1. z 4 i m a afl l 4 4 3 2w? y, a m. v ,2 fl a e 7. a o I a o 4 M M I w a z 3 O a I 0w 7 w M w w 5 a, z M N 3 4, a

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comass oa comer. mncnamsiu JUL 4 1950 Wade H. Wineman, Michigan City, Ind., assignor to Joy Manufacturing Company, a corporation of Pennsylvania Application December 9, 1944, Serial No. 567,410

Claims. (01. 230-4) My invention relates to mechanisms for re ulating the operation of. compressors, and more particularly to mechanisms for regulating the speed of a driving motor for a compressor in ac- On reduction of the receiver pressure. to a predetermined lower value, the pressure responsive means operates to increase the-supply of operating fluid to theengine and to vent the unloading mechanism the venting of-the unloading mechanism being such that the compressor is reloaded alter the driving engine has been brought up to speed. If the drivingvengine is permittedto operate at maximum speed at all times when the compressor is loaded, there will be. under certainconditions of demand for pressure fluid, a frequent unloading and reloadin of the compressor, with changes in the engine speed between maximum and minimum. This to provide an improved mechanismior regulatlug the speed of a compressor in accordance with its discharge pressure. Still another object isto provide improved means for regulating the supply of operating fluid to a driving engine for a cordance with the demand for vcompressed fluid. I fluid compressor. Yet another ,object is to pro- In p sor y ms in wh h a compressor vide improved regulating means for reducing is driven by an n n l combustion engine gradually the supply-ct operating fluid to a drivdeliverins ress d fluid to a r i i tank. ing engine as the compressor discharge pressure it is customary to provide means which is re: increases through a predetermined range. A sponsive o t pressures in the tank for other object is to provide improved regulating trolling the flow'of pressure fluid relative to an means for progressively reducing the supply of unloading mechanism and for regulating the operating fluid to a driving engine as a supply of Operating fluid the -f when pressor driven thereby operates loaded and its the receiver Pressure reaches maximum discharge pressure increases between predetersired value, th pressure "359M151" means Opel" 15 mined values, and operating at a pressure exates Supply Pressure: fluid the unloading ceedlng the higher of said predetermined values mechanism for eflecting an operation of the latfor reducing the Supply f operating fluid to 1- to the compressor at the same iect operation of the driving engine at an idling time reduces. the Supply of P fl to speed with the compressor unloaded. Still anthe engine so that it runs at an idling speed. .20 other object is to provide Speed regulating mechanism having a single element which is actuated by a plurality of pressure responsive devices for regulating the supply of operating fluid to an engine in an improved manner. These and other objects will appear more fully in the, course of the followingdescription.

In the accompanying drawings I have shown for purposes of illustrationseveral forms which my invention may assume in practice.

In these drawings: Fig. 1 is a side elevational view of an internal combustion engine having my improved regulating means in its preferred form associated therewith.

results inan inefficient operation of the compressor system and in a rapid wearing of its Fig. 2 is an enlarged vertical sectional view parts. In order. that there may be an unloading of the regulatingmechamsm shown in of the compressor less frequently, there should 3 is a horizontal Sectional View taken on be provided means for reducing gradually the Plane of the line 3- of Fig. 2.

supply of operating fluid to e engine as the Fig. 4 is a central sectional view through the pressure in the receiver increases through a preunder head and a Portion of the cylinder of a determined range. To prevent the receiver compress adapted to he driven by the engine pressure from dropping below minimum values when the demand for compressed fluid is at a 5 is a Schematic diagram showing the maximum, thepressure pgjnt at which the means 5 ulating mechanism connected into the compresstarts to reducethe engine speed should be somewntrol system- 'what above the minimum desired receiver, pres- 6 is an enlarged Secthmal View thmugh.

sum The upper point of the range may be at a valve mechanism connected in the control sysany higher value and is desirably adjusted to a tem of value somewhat below the pressure at which uni is a side elevational view of a Diesel loading takes place. engine having the improved regulating means of An object of my invention is to provide an 0 s 0 t d h rewlth.

improved speed regulating mechanism for a. fluid Fig. 8 is an enlarged vertical sectional view compressor; Another object of my invention is through a portion of the regulating means for 66 the fuel pump of the Diesel engine and a servo REg32 T motor for controlling the operation of the pump regulating means.

Fig. 9 is a schematic diagram showing the improved regulating mechanism connected in the control system for a Diesel engine operated compressor.

Figs. 10, 11 and 12 are central sectional views showing modified forms of the regulating mechanism.

Referring to Figs. 1 to 6, it will be noted that my improved regulating mechanism in a preferred form is shown associated with an internal combustion compressor driving engine for controlling the supply of operating fluid to the latter in accordance with pressures in a receiver of a compressor system. The internal combustion engine, generally designated I, has a throttle valve 2 which is regulated by my improved regulating mechanism, generally designated 3, and the enginehas its power shaft operatively connected by means, not shown, to a compressor, one piston 5 of which is shown as reciprocable in a bore 5 of a compressor cylinder '5. It will of course be understood that other compressor pistons will normally be employed. Fluid is admitted through an intake passage 9 and past an inlet valve l to the cylinder bore 6 where it is compressed and discharged past a discharge valve l2 to a passage l3 which is connected by suitable connections, not shown, to a receiver I i, shown in Fig. 5. The cylinder is provided with a head member l5 having a chamber l6 which receives a piston l8 carrying a plate portion l9. Rods 28 are connected to the plate portion l9 and extend through openings in the cylinder head to engage the inlet valve II! for unseating the latter and eflecting an unloading of the compressor when the piston I8 is subjected to pressure fluid. The piston. I8 is normally held in its raised position by a spring 22 and is adapted'to be forced to its lower position against the action of the spring 22 by pressure fluid supplied to the chamber l5 through a conduit 24.

' The improved regulating means 3 comprises a cylinder block 26 having a flange portion 21 which is adapted to be connected to the side of the engine, as by bolts 28. Formed in the cylinder block is a bore 30 opening through one end of the block and covered at its open end by a cover plate 3|. Arranged in the bore '30 is a bellows device 32 which is connected at its ends, as by brazing, to the cover plate 3| and to a member 33 having a tongue portion 34'which is reciprocably received within a recess 35 formed in the cylinder block 26 at the inner end of the bore 30. The member 33 is provided with a sleeve portion. which projects axially through the bellows device 32 for a substantial distance. Formed in the plate member 3| is an opening 31 through which'an elongated member 38 projects, and the inner end of this member 38 is provided with a portion 39 which is reciprocably received within the sleeve portion 36. The opening 31 provides a substantial clearance around the member 38 whereby the interior of the bellows device is connected in free communication with the atmosphere, At the outer end of the member 38 there is an enlarged portion 40 having an opening 4| through which a control lever 42 extends, and the control lever is pivotally connected to this enlarged portion by a transversely extending pin 44. Connected to the outer side of the cover plate 3| below the opening 31 is a support member 48 having a bore 41 which reciprocably receives a plungerlike member. 48. The lunger- 4 like member 48 is slotted transversely at 49, and the support member 48 is provided at the upper side of the bore 41 with an opening 50 through which the lower end of the control lever projects into the slot 48. A pin 52 pivotally connects the lower end of the control lever to the plunger 48. A spring 53 acts between the plunger 48 and the plate 3| for holding the plunger normally in engagement with a pin 54 extending transversely through the bore 41. The support member 46 is provided with an upwardly projecting portion having an opening 55 through which a screw 55 is threaded to a position where it'is engageable by the enlarged end portion 48 of the elongated member 38. A lock nut 51 is provided for holding the screw 56 in its adjusted position. Pressure fluid is supplied continuously from the receiver M through a conduit 60 to the bore 30 where it acts on the bellows device 32 and tends to compress the latter. As the bellows device is compressed by the pressure fluid, the member 33 engages the inner end of the elongated member 38 and moves the latter in a direction to swing the control lever 42 about the pivot pin 52.

The cylinder block- 26 is provided with an upwardly projecting portion 62 having an opening 83 extending lerethrough, and an elongated '.'member 66 has one end fixed securely within the 7 opening 63 and projects forwardly from the portion 62 with its axis substantially parallel to the axis of the bore 38. Slidably mounted on the member 64 is a sleeveshaped member 65 which is closed at its outer end and is pivotally connected by a link 81 to a pin 68 carried by the control lever 42. Extending longitudinally through the member 84 is a passage 10 for contlon I5, and a spring I6 has one of its ends engageable with a toothed section 'I'I of the control lever 42 and its other end connected to a screw 18 which extends through an opening in the upwardly bent portion 15. A nut 19 is threaded on the outer end of the screw 18 and engages the rod portion 15 for holding the spring 16 in its adjusted position.

The upper end of the control lever 42 is provided with an opening 80, and a rod 8 I, connected at one end to an arm 82 attached to the throttle valve 2, extends freely through the opening and has a nut 83 threaded on its outer end for preventing release of the rod 8| from the control lever 42. Fixed to the rod 8| is a sleeve member 84, and a spring 85 acts between this sleeve member and the control lever 42 so that movements of the control lever in a clockwise direction, as shown in Fig. 1, operate through the spring 85 for moving the throttle valve 2 in a closing direction. Movement of the control lever 42 by the supply of pressure fluid to the interior of the sleeve 65 is limited, as shown in Fig. 3, by an abutment pin 86 which is engageable by a projecting boss portion 81 formed on the sleeve member 65. In order that the regulating mechanism may be locked in any desired position, there is provided a member 88 threaded through openings in the boss portion 81 and the sleeve member 65 to engage the member 64. An operating handle is provided ior'manually adjusting the member 88 into its clamped and released positions.

As shown in Fig. 5, the receiver I4 is connected by a conduit 90 to a pilot valve 9I of a well-known type which operates at a predetermined maximum pressure for connecting the conduit 90 in communication with a conduit 92, and which operates at a predetermined lower pressure for connecting the conduit 92 in communication with the atmosphere. The conduit 92 is connected to conduits 99 and 94 communicating respectively with the passage extending through the member 64 and with a valve casing 95. The valve casing 95, as shown in Fig. 6, is provided with a passage 99 connecting the conduit 94 in communication with the interior of the casing past a ball valve 98 which is yieldably held in its closed position by a spring 99. A passage I00 also connects the conduit 94 in communication with the interior of the casing, and an adiustable member IN is provided for restricting the flow of fluid through the passage I00. The interior of the casing is connected by a conduit I02 in communication with the conduit 24 leading to the plunger I8 of the compressor unloading mechanism. As shown in the diagram of Fig. 5, two conduits 24 are provided leading to compressor unloading mechanisms, the compressor in this case having two cylinders. Of course, in practice, this number would usually be exceeded. p

The point at which the speed regulating mechanism starts to slow down the engine is determined by the tension on the spring 10, this being adjusted by varying the position of the spring on the toothed portion of the lever 42 and by reg-- ulating the nut I9 until operation is obtained at the desired pressure. The compressor'may be driven atamaximum speed, say 1200 R. P. M., until, say, a pressure of 90 pounds is reached, this being the pressure at which it is proposed that the spring 18 be adjusted to commence to yield to the force exerted on the lever 42 by the bellows device 32'. As the receiver pressure continues to increase, the bellows device will be com-- pressed and cause the control lever 42 to swing about the pivot pin 52 and move the rod 9| in a direction to close the throttle valve 2. The characteristics and ad ustment of the spring I6 may also desirably be made such that, under the conditions selected for purposes of illustration, the control lever 42 will be moved. on an increase in receiver pressure to 95 pounds, to a point where the throttle valve will be sufficiently restricted to reduce the speed of the engine to, say, approximately 800 R. P. M. The screw 56 is so adjusted 6 gine. The abutment pin 80 is desirably adjusted,

under the conditions selected for pur poses of illustration, to limit the outward movement of the sleeve member 60 to a point'wher'e the'restrictionby the throttle valve 2 is such that the englue is reduced to an idling speed of 450 R. P. M.

As the control lever swings about the pivot pin 44, the lower end of the control lever will swing to the left, as shown in Fig. 2, and move the plunger 48 against the action of the spring 53.

-At .the same time that the pressure fluid flows from the conduit 92 to the conduit 03, it also flows to the conduit 94 and is conducted to the valve mechanism 95 where it acts to unseat the ball valve 98. The fluid flows freely past the ball valve to the conduit I02 which conducts itto' the that it isengaged by the outer end of the elongated member 38 just as the receiver pressure of gine, and the engine will continue to operate at approximately 800 R. P. M. even though the receiver pressure may slightly increase. When the receiver pressure increases to the maximum desired value, say 100 pounds, the pilot valve 9| operates to supply pressure fluid from the receiver through the conduits 90, 92, 93 and the passage 10 to the inner end of the sleeve member 65. The pressure fluid acting on the sleeve member 05 causes the latter to move outwardly and swing the control lever 42 about the pivot pin 44 in a direction to restrict further the supply oi actuating fluid to the internal combustion enpressure.

conduits 24 communicating with-the unloading mechanisms for the compressor cylinders.

It will be seen that the compressor will be immediately unloaded and will continue to be driven unloaded at an idling speed as long as pilot valve 9I remains in its open position. when the receiver pressure drops to a predetermined lower value, for instance 95 pounds, the pilot valve operates to vent the conduit 92 to atmosphere. Pressure fluid then escapes immediately from the interior of the sleeve member and the spring I6 swings the control lever about the pivot pin 44 until the plunger 48 at the lower end of the control lever is moved into engagement'with the pin 54. The bellows device 32 is held compressed by the 95 pounds pressure so that the outer end of the member 38 continues to engage the pin 54 and holds the control lever'against swinging movement about the pin 52. The position of the control lever at this time is such that the eng ne speed is increased to 800 R. P. M. The escape of fluid from the unloading mechanism is restricted since the ball valve 98 moves to its closed position and the pressure fluid can escape only through the passage I00 to the conduit 94. By the time the pressure fluid has escaped from the unloading mechanisms and the compressor cylinders have been reloaded, the driving engine will already'have increased to 800 RP. M. and will continue to driveithe compressor loaded at this speed unless there is a further drop in receiver If the receiver pressure continues to drop, the reduction of pressure on the bellows device 32 will result in a swinging oi. the-control lever about the pin 52 in a'direction to open further the throttle valve 2 and cause the engine to increase its speed.

In Figs. '7, 8 .and 9, there is shown a regulating mechanism, like that of Figs. 1 to 6, connected to a Diesel engine I05 for controlling the supply of operating fluid to the latter. The engine is provided with the usual fuel pump I06 having a conventional control mechanism which includes, as shown in Fig. 8, a control rod I01. The end of the control rod is connected to the lower end of 4 an arm I08 which is pivotally supported at its by the casing I I0. In Fig. 8 the lever I I2 is shown in what may becalled full-load position, and movements of the lever clockwise in Fig. 8 effect a slowing down of the engine and compressor. Considerable force is required to swing the lever H2 about its pivotal mounting in a counterclockwise direction and so there is provided a servo motor, generally designated I I4, operatively the right-hand end of the piston I I1.

- operati' nby the regulating mechanism 3.

.The ervo motor includes a cylinder member I I having a bore II5 which slidably receives a piston I I1 connected by a rod II8 to the upper end of the lever II2. The piston is provided with an elongated annular groove I in its periphery, and pressure fluid is-supplied to this annular groove by a hydraulic pump I2I arranged, as shown in Fig. 9, in the crankcase of the engine and connected by a conduit I22 to a port I23 opening into the bore I I6 between the ends of the latter. The piston H1 is provided with an axial bore I24 and a radial passage I25 connecting the groove I20 to the bore I24 at a point adjacent the inner end of the latter. Radial passages I26 and I29 open into the bore I24 at longitudinally spaced points and are connected by a passage I30 to the space within the bore H6 at Slidably received within the bore I24 is a piston member I32 having a head portion I33 which is adapted to control the communication of the passages I25 and I28 with the bore I24. Formed in the piston member I32 is an annular groove I35 which is adapted to connect the passage I23 in communication with grooves I36 extending longitudinally in the outer periphery ofthe piston member to points where they communicate with the bore I I6 at the left-hand end of the piston when the annular groove I35 communicates with the passage I28. The passages I25, I28 and I29 are so arranged that a movement of the piston member I32 to the left covers the passage I28 and uncovers the passage I25 permitting fluid to flow from the passage I25 to the bore I24 where it enters the passage I29 and is conducted to the cylinder bore II6 at the right-hand side of the piston. When. the piston member I32 is moved to the right, the passage I25 is covered by the head portion I33 and the passage I28 is connected in communication with the annular groove I35 so lever II2 reduces the tension of the spring III I and so effects a slowing down of the Diesel engine,

since the control rod I01 can the more readily be moved to the left. When the control lever 42 swings in a counter-clockwise direction, the pora the piston where it acts on the latter to eflect its movement in a direction to swing the lever II2 about its pivot for reducing the supply of operating fluid to the engine.

In Fig. 10, there is shown a modification of the invention in which a control lever I50 is pivotally' connected at its upper end to a rod I5I which may be connected directly to the throttle valve of an internal combustion engine, as shown in Figs. 1 to 6, or to a servo motor which operates control means for a Diesel engine, as shown in Figs. '7 to 9. The lever I50 is pivotally connected at a point between its ends to a rod I52 having stepped portions I53 and I54 which are slidably supported by bushings I55 and I56 threadedly mounted in openings I51 and I58 formed in upwardly projecting portions of a block I59. Connected to one end of the block I59 in alinement with the bushings I55 and I 56 is a casing I60 containing a bellows device I6I which is connected, as by brazing, at one end to an annular plate member I62 clamped between the casing I60 and that the space in the bore H6 at theright-hand end of the piston is vented through the passages I30, I28, the annular groove I35, and the-grooves I36 to the bore II 6 at the left-hand end of the piston where it is drained away through a conduit'l38 leading to the crankcase of the engine.

The piston member I32 is shown herein as forming a portion of a rod I40 which is connected, as shown in Fig. '7, to an arm I4I pivoted at I42 in any suitable way on a stationary axis. A manually controlled arm I43 is movable to control the position of the arm I4I and is securable by a nut I44 in difi'erent positions to limit the maximum speed of the unit if desired. Normally, however, the arm I43 remains in the position shown in Fig. '7, and the rod I40 is controlled exclusivelly by the regulating mechanism through the control lever 42 which is pivotally connected at I to the rod I40.

The operation ofthe regulating mechanism is the same as that described above. As the control lever 42 swings in a clockwise direction, the rod I40 moves with the lever and positions the piston member I32 so that its portion I33 covers the passage I25 and uncovers the passage I28 connecting the latter to the groove I35 so as to vent liquid from the right-hand end of the bore H6. The spring III then causes the arm II2 to swing about its pivotal support and move the piston II! to the right until'the passage I28 is again covered by the piston portion I33 and the escape of fluid from the right-hand end of the cylinder bore is cut oil. This swinging of the the block I59 and at its other end to a movable plate member I63. The rod portion I54 extends axially through the bellows device and is connected at its end to the plate member I63, as shown. A spring I64 surrounds the rod portion I54 and acts between the bushing I56 and the movable plate I63 for holding the bellows device normally expanded with the plate member I63 held in engagement with an adjustable bolt I65 having a. lock nut I66. Pressure fluid is supplied continuously from the receiver through a conduit I68 to the space in the casing I60 surrounding the bellows device. Formed in the block I59 is a chamber I10 which is enclosed at one end by a cover plate "I, and arranged within the chamber I10 is a bellows device I12 which is connected, as by brazing, soldering, etc., at one end to the cover plate "I and at its other end to a movable plate I13. Formed on the plate I13 is a projecting portion I14. which extends through an opening I15 in a partition I16 separating the inner end of the chamber I10 from a chamber I11. A spring I18 acts between the inner end of the chamber I 10 and the plate I13 for holding the bellows device I12 normally compressed. A pin I19 projects radially from the projecting portion I14 and is engageable with the partition I16 for limiting the compression of the bellows device I12. A conduit I is connected through an opening I8I in the cover plate I1I in communication with the interior of the bellows device I12 and supplies pressure fluid from a pilot valve, such as that shown in Fig. 5, to the interior of the bellows when the receiver pressure reaches a predetermined maximum value. Threaded into an opening in the block in alinement with the projecting portion I14 is a bolt I83 which is engageable by the projecting portion for limiting the expansion of the bellows device I12. The lower end of the lever I50 is provided with several openings I85 for selectively receiving a pivot pin I86 to which one end of a of the links I91 are operatively connected to the platemember I13.

It will be seen that the pressure fluid acting on the exterior of the bellows device I operates to'compress the latter against the force the spring I54 and to move the rod I52 in a direction to swing the control lever about the pivot pin I36. The shoulder formed at the juncture of the stepped portions I53 and I54 of the rod I52 engages the bushing I55 and limits the swing of the lever I59 in a clockwise direction. The adjustment of the bushing I55 within the opening I51 therefore determinesv the minimum speed that may be obtained through the compression of the bellows device II. By adJusting the bushing wt to vary the compression of the spring I54, the operation of the bellows device Iii may be obtained at any desired pressure. The adjustment of the bolt I95 determines the distance that the control lever may be swung in a counter-clockwise direction and therefore the maximum speed oi the driving engine. After the receiver pressure has increased to the point where the rod I52 is moved to its extreme right-hand position for repair or links I91 are connected. The other end piston I32 is in any of its various positions, and

ducing the speed of the engine, no further change will take place until the receiver pressure has increased to the point at which the pilot valve opens and supplies pressure fluid through the conduit M9 to the interior of the bellows device I12. On the supply of pressure fluid to the interior of this bellows, the plate member I13 is forced to the left until its projecting portion I14 engages the bolt E83. The movement of the plate member I19 to the left causes the links I81 to swing the lever 59 in a clockwise direction about its pivotal connection to the rod I52 and actuate the rod IN to effect a further slowing down of the engine to an idling speed.

In the form of the invention shown in Fig. 11 there is provided a cylinder member I99 having a bore I9I which reciprocably receives a. piston member I92. member I94 threaded into one or its ends and is provided at its other end with a flared portion I95. A diaphragm I99 is clamped between the flared portion I95 and a cap I91, and reinforcing plates I96 are clamped to opposite sides of the diaphragm by a bolt I99 having its'head engageable with the piston I92. The cap I91 and the flared portion I95 form a chamber 299 which permits substantial movement of the diaphragm I96 and its reinforcing plates I98. Pressure fluid is supplied continuously from the receiver through a conduit 29I to the chamber 299 at the side of the diaphragm opposite the piston I92. A spring 294 acts between the piston I92 and the annular member I94 for resisting movement of the piston by the diaphragm. The piston I92 is provided with axially projecting stepped portions 299 and 291, the portion 291 extending loosely through an annular member 299 which is threaded. into the annular member I94. The shoulder 2| 9 at the juncture of the stepped portions 299 and 291 is engageable with the member 293 for limiting movement of the piston I92 by the diaphragm I95. The piston I92 and its larger proiecting portion 299 is provided with an axial bore 2I2 which slidably receives a piston 2I3 having a piston rod 2I4 which is slidably received within an opening 2 I5 extending axially through The cylinder I99 has an annular.

an annular groove 2I9in its periphery and a radial passage III connecting the groove 2 in communication with the bore 2I2. A conduit 229 is connected hy a port 22I in the cylinder member I99 is communication with the bore I9I at a point to communicate with the groove 2I3 when the pressure fluid is supplied from the receiver to the conduit 229 under the control of a pilot valve. The piston rod 2I4.is provided with a member 223 to which suitable regulating means for an engine may be connected.

The operation or this form of regulating means is as follows; As the receiver pressure increases and finally moves the diaphragm I95 to the right forcing the piston I92 with it against the action of the spring 294, the piston 2I3 moves with the piston I92 in a direction to cause an actuation of the fluid regulating means connected to the rod 2I4 so as to slow down the driving engine. when the shoulder 2 I9 is moved into engagement with the annular member 299, further movement of the piston I92 by the diaphragm I99 will be prevented. The engine will then operate at a reduced speed until the receiver pressure increases to the point at which the pilot valve opens and supplies fluid through the conduit 229 to the annular groove 2I9 in the piston I92. Pressure fluid supplied to this groove flows throughthe radial passage 2I9 to the bore 2I2 at the left-hand end of the piston 2I3 where it acts on the piston and causes the latter to move to the right within the bore 2I2 against the action of the spring 2" and eflect a slowing down of the engine to an idling speed. Equalization of pressure at the right of piston 2I3 with that at the left, due to leakage, is prevented by reason of the existence of adequate space for leakage around the rod 2I4.

In Fig. 12, there is shown another modification of the invention inwhich a block 239 is provided with parallel bores 23! and 232 containing pistons 233 and 234. The piston 233 is provided with a piston rod 235 having stepped portions 231 and 239, the portion 238 extending through an opening in an annular member 239 whlch is threadedly received in an annular member 249 threaded into the right-hand end of the bore 23 I. A spring 242 acts between the annular member 249 and the piston 233 for holding the latter normally at the left-hand end of the bore 23I. The shoulder formed at thejuncture of the stepped-portions 231 and 233 is engageable with the annular member 239 for limiting movement of the piston 233 to the right within the bore 23I. Receiver pressure is supplied continuously through a conduit 245 to the left-hand end of the bore 23I where it acts on the piston 233 and tends to move the latter to the right against the action of the spring 242. The outer end of the piston rod 235 is pivotally connected at 249 to one end of a control lever 241 which is pivotally connected between its ends to a control rod 249. The piston 234 is provided withya piston rod 259 which extends through a plug 25I closing the right-hand "for urging the piston 234 toward the left-hand end of the bore 232. A conduit 253 communicates with the left-hand end of the bore 232 and is I adapted to be connected in communication with a receiver or with atmosphere under the control of a pilot valve.

The receiver pressure acting continuously on the piston 232 forces the latter against the spring 242 as the receiver pressure increases and causes the lever 24'! to swing about the pivot connection 254 and move the control rod 248 in a direction to restrict the supply of operating fluid to the driving engine. The tension 01 the spring 242 may be adjusted by regulating the annular member 240 so that operation of the piston 233 is obtained at the desired pressure values, and the distance that the piston may move to the right is determined by the adjustment of the annular member 239, When the receiver pressure reaches the predetermined maximum value and the pilot valve operates to supply pressure fluid through the conduit 25!! to the bore 232, the piston 234 is forced to the right against the action of the spring 242 and causes the lever 241 to swing about its pivot connection 246 and move the rod 248 in a direction to restrict further the supply of operating fluid to the driving engine. With each of the last two species of the invention a stop for the motion of the throttle or other control device can be provided to limit the movements effected by the rods 2 and 250 under fluid pressure applied to their pistons.

As a result of my invention there is provided an improved mechanism for regulating the supply of operating fluid to a driving engine for a compressor. The regulating mechanism is very compact and is readily adjusted to operate at the desired pressures for effecting a regulating of the engine speed in an improved manner. In each of the forms of the invention a single element is actuated by a plurality of pressure responsive devices for regulating the supply of operating fluid tothe engine. The adjustments provided permit the element to respond to the pressure responsive devices within any desired pressure range for varying the speed of the engine. In each case the control element is actuated by one of the pressure responsive devices to effect a gradual variation in the speed of the engine as the pressure changes through a predetermined range, and is actuated by another pressure responsive device to slow down the engine to an idling speed when the pressure reaches a predetermined maximum value.

While there are in this application specifically described several forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration, and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. A speed regulating mechanism for a motor driven compressor comprising, in combination,

means including a control element movable to vary the supply of operating fluid to the motor,

means for yieldingly urging said control element in a direction to increase the supply of operating fluid, a plurality of pressure responsive devices for moving said control element against the action of said yielding means, said yielding means providing substantially the entire resistance to movement of said pressure responsive devices, means for subjecting one of said pressure responsive devices continuously to compressor discharge pressure, and means for subjecting another of said pressure responsive devices to compressor discharge pressure when a predetermined maximum pressure is reached.

2. A speed regulating mechanism for a motor driven compressor comprising, in combination, means including a pivoted control lever for regulating the supply of operating fluid to the motor, a plurality of fluid pressure responsive devices supported to act in like direction under the action of fluid pressure thereon and pivotally con nected to said control lever at points spaced longitudinally of the latter but at the same side of the pivot thereof, means for subjecting one of said pressure responsive devices continuously to compressor discharge pressure, and means for subjecting another of said pressure responsive devices to compressor discharge pressure when a predetermined maximum pressure is reached.

3. A speed regulating mechanism for a motor driven compressor comprising, in combination, means including a control lever for regulating the supply of operating fluid to the motor, a support member pivotally supporting said control lever at one end of the latter, means for supporting said member for limited bodily movement in a direction transversely of said control lever, a plurality of pressure responsive devices pivotally connected to said control lever at points spaced longitudinally of the latter, means for subjecting one of said pressure responsive devices continuously to compressor discharge pressure, and means for subjecting another of said pressure responsive devices to compressor discharge pressure when a predetermined maximum pressure is reached.

4. A speed regulating mechanism for a motor driven compressor comprising, in combination, means including a 'control lever for regulating the supply of operating fluid to the motor, a support member pivotally supporting said control lever at one end of the latter, means for supporting said member for limited bodily movement in a direction transversely of said control lever, means for yieldably resisting the swinging of said control lever in one direction about said support member, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof and operative on the supply of pressure fluid thereto for swinging said lever against the action of said yielding means, means for subjecting one of said pressure responsive devices continuously to compressor discharge pressure, and means for subjecting the other of said pressure responsive devices to compressor discharge pressure when a predetermined maximum pressure is reached.

5. A speed regulating mechanism for a motor driven compressor comprising, in combination, means including a control lever for regulating the supply oiv operating fluid to the motor, a support member pivotally supporting said control lever at one end of the latter, means for supporting said member for limited bodily movement in a direction transversely of said control lever, means for yieldingly urging said control compressor discharge pressure, and means for subjecting the other of said pressure responsive devices to compressor discharge pressure when a predetermined maximum pressure is reached.

6. A speed regulating mechanism for a motor driven compressor comprising, in combination, means including a control lever for regulating the supply of operating fluid to the motor, asupport member pivotally supporting said control lever at one end of the latter, means for supporting said member for limited bodily movement in a direction transversely of said control lever, means for yieldingly urging said control lever in a direction to increase the supply of operating fluid to the motor, a pair of pressureresponsive devices pivotally connected to said lever at points spaced longitudinally thereof difierent distances from said support member and operative on the supply of pressure fluid thereto for swinging said control lever against the action of said yielding means, means for limiting the swinging of said control lever by said pressure responsive devices, means for subjecting the one of said pressure responsive devices nearer to said support member continuously to compressor discharge pressure, and means for subjecting the other of said pressure responsive devices to compressor discharge pressure when a predetermined maximum pressure is reached.

7. A speed regulating mechanism for a motor driven compressor comprising, in combination,

means including a control lever for regulating the supply of operating fluid to the motor, a support member pivotally supporting said control lever at one end of the latter, means for supporting said member for limited bodily movement in a direc tion transversely of said control lever, means for yieldin'gly urging said control lever in a direction to increase the supply of operating fluid to the motor, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof different distances from said support member and operative on the supply of pressure fluid thereto for swinging said control lever against the action of said yielding means, means for subjecting the one of said pressure responsive devices nearer to said support member continuously to compressor discharge pressure, adjustable means for limiting the swinging of said lever by said pressure responsive device, means for subjecting the other of said pressure responsive devices to compressor discharge pressure after the limit of swing of said lever by said first mentioned pressure responsivedevice has been reached.

8v A speed regulating mechanism for a motor driven compressor comprising, in combination, a control lever for regulating the supply of operating fluid to the motor, a support memberpivotally supporting said control lever at one end of the latter, means for supporting said support mem her for limited bodily movement in a direction transversely of said lever, yieldable means operatively connected to said lever at a point adjacent its other end for urging said lever in adirection to increase the supply of operating fluid to the motor, a pair of pressure responsive devices operatively connected to said lever between said support member and said yieldable means and at points spaced difierent distances from said support member, said pressure responsive devices operative to swing said lever in a direction to reduce the supply of operating fluid to the motor, means for subjecting one of said pressure responsive devices continuously to compressor discharge pressure, means for subjecting the other of said pressure responsive devices to compressor dis-j 14 charge pressure after a predetermined maximum pressure is reached, and adjustable means for limiting the swinging 0! said lever by each of said pressure responsive devices.

9. A speed regulating mechanism for a; motor driven compressor comprising, in combination, a control lever ior regulating the supply of operating fluid to the motor, a support member pivotally supporting said control lever at one end of the latter, means for supporting said support member for limited bodily movement in. a direction transversely of said lever, yieldable-means operatively connected to said lever at a point adjacent its other end for urging said lever in a direction to increase the supply of operating fluid to the motor, a pair of pressure responsive devices operatively connected to said lever between said support member and said yieldable means and at points spaced difierent distances from said support member, said pressure responsive devices operative to swing said lever in a direction to reduce the supply of operating fluid to. the motor, means for subjecting the one of said pressure responsive devices connected to said lever at the point nearer said support member continuously to compressor discharge pressure, adjustable means for limiting the swinging of said lever by said pressure responsive device, and means for subjecting the other 0! said pressure responsive devices to compressor discharge pressure after the swing of the lever by said first pressure responsive device has been limited by said adjustable means.

10. A speed regulating mechanism for a motor driven compressor comprising, in combination, a control lever for regulating the supply of operating fluid to the motor, a support member pivotally supporting said control lever at one end of the latter, means for supporting said support member for limited bodily movement in a direcsure, adjustable means for limiting the swing of said lever by said pressure responsive device,

means for subjecting the other of said pressure responsive devices to compressor discharge pres sure after such compressor discharge pressure has increased to a value above that at which movement of said lever by the flrst of said pressure responsive devices is limited.

11. A speed regulating mechanism for an engine driven compressor comprising, in combination, a control lever, means operatively connecting said lever at one end to fuel regulating means for the engine, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof different distances from said connecting means, means forsubjecting the one of said pressure responsive devices connected to said lever nearer said connecting means continuously to compressor discharge pressure, and means for subjecting the other of said pressure responsive devices to compressor dis-: charge pressure when a predetermined maximum pressure is reached.

12. A speed regulating mechanism for an engine driven compressor comprising, in combination, a control lever, means operatively connectfor the engine, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof diflerent distances from said connecting means and each operative by pressure fluid supplied thereto to swing said lever about its pivotal connection to the other in a direction to effect a reduction of fuel supply to the engine, means for subjecting the oneof said pressure responsive devices conne'cted'to said lever nearer said connecting means continuously to compressor discharge pressure, and means for subjecting the other of said pressure responsive devices to compressor discharge pressure when a predetermined maximum pressure is reached.

13. A speed regulating mechanism for an engine driven compressor comprising, in combina-- tion, a control lever, means operatively connecting said lever at one end to fuel regulating means for the engine, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof diiferent distances from said connecting means and each operative by pressure fluid supplied thereto to swing said lever about its pivotal connection to the other in a direction to effect a reduction of fuel supply to the engine, means for limiting the operation of the one of said pressure responsive devices connected to said lever nearer said connecting means by the pressure fluid supplied thereto, means for subjecting said last mentioned pressure responsive device continuously to compressor discharge pressure, and means for subjecting the other of said pressure responsive devices to compressor discharge pressure after such compressor discharge pressure has increased to a value above that at which operation of the first mentioned pressure responsive device is limited.

14. A speed regulating mechanism for an engine driven compressor comprising, in combination, a control lever, means operatively connecting said lever at one end to fuel regulating means for the engine, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof different distances from said connecting means and each operative by pressure fluid supplied thereto to swing said lever about its pivotal connection to the other in a direction to effect a reduction of fuel supply to the engine, adjustable means for limiting the operation in each direction of the one of said pressure responsive devices connected to said lever nearer said connecting means, means for subjecting said last mentioned pressure responsive device continuously to compressor discharge pressure, means for subjecting the other of said pressure responsive devices to compressor discharge pressure after such compressor discharge pressure has increased to a value above that at which movement of the first pressure responsive device by the fluid supplied thereto is limited, and adjustable means for limiting the operation of said other pressure responsive device by the pressure fluid supplied thereto.

15. A speed regulating mechanism for an engine driven compressor comprising, in combination, a control lever, means operatively connecting said lever at a point between its ends to fuel regulating means for the engine, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof and at opposite sides of said connecting means, means for subjecting one of said pressure responsive devices continuously to compressor discharge presing said lever at one end to fuel regulating means lever at a point between its ends to fuel regulating means for the engine, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof and at opposite sides of said connecting means and each operative by pressure fluid supplied thereto to swing said lever about its pivotal connection to the other in a direction to effect a reduction of fuel supply to the engine, means for subjecting one of said pressure responsive devices continuously to compressor discharge pressure, and means for subjecting the other of said pressure responsive de- :vices to compressordischarge pressure when a means for the engine, a pair of pressure responsive devices pivotally connected to said lever at points spaced longitudinally thereof and at opposite sides of said connecting means and each operative by pressure fluid supplied thereto to swing said lever about its pivotal connection to the other in a direction to effect a reduction of fuel supply to the engine, means for subjecting one of said pressure responsive devices continuously to compressor discharge pressure, means for limiting the operation of this pressure responsive device by pressure fluid, and means for subjecting the other of said pressure responsive devices to compressor discharge pressure after such compressor discharge pressure has increased to a value above that at which operation of the first pressure responsive device is limited.

18. In a speed regulating mechanism for an engine driven compressor in which throughout the range of loaded operating speeds a speed responsive governor variably controls the speed of a compressor as the force opposed to the action of the driving engine governor is varied, in combination, a control element movable to vary the force opposed to the action of the governor to cause the latter to exercise a variable speed control, and means for moving said control element in a direction to reduce the force opposed to the action of the governor and to permit the latter to reduce the operating speed of the compressor including a plurality of pressure responsive devices each movable by the action of fluid pressure thereon to effect movement of said controlelement in said direction, means for subjecting one of said devices continuously to compressor discharge pressure, 'and means. for subjecting another of said pressure responsive devices to compressor discharge pressure only when a predetermined maximum pressure is reached.

19. In a speed regulating mechanism for a motor driven compressor, in combination, means including a control element movable to regulate the supply of operating fluid to the compressor driving motor, a plurality of pressure responsive devices each movable under fluid pressure to alter the position of said control element to effect slowing down of said engine, means for subjecting one of said pressure responsive devices continuously to compressor discharge pressure. means for subjecting another of said pressure responsive de- .17 vices to compressor discharge pressure when a predetermined maximum pressure is reached, a member pivotally connected to said control element and upon which said pressure responsive devices act at different points, a speed responsive device having means for opposing its operation in response to speed increases, and means operated by said member for varying the action of said last mentioned means.

20. In a speed regulating mechanism for a motor driven compressor, in combination, a pressure responsive device constantly subjected to compressor discharge pressure during normal operation of the motor driven compressor and movable freely in accordance with compressor discharge pressure variations to vary the motor speed between a maximum speed desired for pumping operation and a. minimum speed desired for pumping operation, said pressure responsive device including apivoted lever having a motor speed controlling connection at point spaced from its pivot, resilient means acting on said lever for resisting motion thereof in a direction to reduce motor speed and imposing on said lever a resistance to movement such as to prvoide a progressive reduction in motor speed as compressor discharge pressure increases, and a pressure responsive element subjected on one side thereof continuously to compressor discharge pressure and v cooperating with said lever at a point between the REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,812,057 Neale June 30, 1931 2,171,285 Baker Aug. 29, 1939 2,212,631 Baker Aug. 27, 1940 2,221,855 Bartholomew Nov. 19, 1940 2,255,095 Baker Sept. 9, 1941 

